Algorithm for crest detection based on graph contraction

The concept of graph contraction was developed with the intention to structure and describe the image segmentation process. We consider this concept to describe a new technique of crest lines detection based on a definition of water-parting (or watershed). This technique allows to localize the basins delimited by these lines. The localization process uses the concept of ascending path. A structure of oriented graph is defined on original image. We give some definitions we use for this process. Before presenting the contraction algorithm, a pretreatment on the oriented original graph is necessary to make it complete. We show the algorithm resultson simple image examples.